EJ101 Posted January 24, 2016 Posted January 24, 2016 because we were hijacking gav240z build thread, I thought I'd start a new topic here. Lurch you mentioned Les Collins is building an L24 with an 89mm crank. Does Les Collins make these cranks? What is cost of such a crank? Quote
CBR Jeff Posted January 24, 2016 Posted January 24, 2016 Details are in my build thread but basically. Les said the crank starts life as an RB crank then gets modified with the journals reduced and off set ground to increase the stroke. Or something like that. So it has a 89 mm stroke makes it just over 3 ltrs. Your best bet would be to talk to Les about availability and pricing. As always good things cost money. Jeff Quote
dat2kman Posted January 24, 2016 Posted January 24, 2016 Or go to the mb that make cranks from scratch? Bit pricey, They're in Melbourne somewhere,,, Quote
C.A.R. Posted January 24, 2016 Posted January 24, 2016 (edited) LCR have the cranks modified. Cost is around $2500. Les is having longer flywheel bolts made by ARP, so a std L6 flywheel can be used with a spacer, instead of having a billet flywheel made (the flywheel mounting face is shorter on a RB crank and a L6 flywheel won't bolt up). Or go to the mob that make cranks from scratch? Bit pricey...They're in Melbourne somewhere,,, Yes, a news billet stroker 6 cylinder crank from Auscrank is $7000.I'll stick with my modified RB item, thanks... Edited January 24, 2016 by Lurch ™ CBR Jeff and gav240z 2 Quote
d3c0y Posted January 24, 2016 Posted January 24, 2016 And to clarify it makes a 3.35L with an over-bored and clearenced L28 block not an L24. Quote
EJ101 Posted January 25, 2016 Author Posted January 25, 2016 is the 90mm crank in Green Hornet done the same way........from an RB? yes $7000 for a crank is pricey. Quote
C.A.R. Posted January 25, 2016 Posted January 25, 2016 (edited) is the 90mm crank in Green Hornet done the same way........from an RB? yes $7000 for a crank is pricey. No, the one on the Green Hornet is a billet - So Greg spent $7k.It IS fully counter-weighted though - the RB isn't. Motorsport isn't cheap - How fast do you want to go? Edited January 25, 2016 by Lurch ™ Quote
road rider Posted January 25, 2016 Posted January 25, 2016 Motorsport isn't cheap - How fast do you want to go? Yes that comment did make me laugh! Quote
Moderators PB260Z Posted January 25, 2016 Moderators Posted January 25, 2016 Motorsport isn't cheap - How fast do you want to go? Yep very true. However this is my favourite Power, Reliability, Cheap Choose only two !! Quote
d3c0y Posted January 25, 2016 Posted January 25, 2016 Does it count if you are cheap and the car is the other two? Quote
Moderators PB260Z Posted January 25, 2016 Moderators Posted January 25, 2016 Does it count if you are cheap and the car is the other two? Haha - I like the way you think Quote
EJ101 Posted January 25, 2016 Author Posted January 25, 2016 when I do get a Z, whatever it may be, I don't intend on setting any land speed records so very unlikely I'll be spending $7k on a crank, $2500 maybe. my questions have been purely out of curiosity. $7k for a locally made counterweighted 90mm crank is reasonable. Kameari L6 3.1L race crank is about $7500 U.S Quote
road rider Posted January 25, 2016 Posted January 25, 2016 Back on topic... What will be the end result as far as engine capacity using the L24 engine and 89mm crank that Les Collins is building. Just another thought.....Why not modify an L series crank and turn it into a stroker? Quote
C.A.R. Posted January 25, 2016 Posted January 25, 2016 Back on topic... What will be the end result as far as engine capacity using the L24 engine and 89mm crank that Les Collins is building. Just another thought.....Why not modify an L series crank and turn it into a stroker? That's a bit of an open ended question, but with a std L24 bore of 83mm, with the 89mm stroke crank it makes it 2889cc With a 84mm overbore it becomes 2959cc With a 85mm overbore it becomes 3030cc Yes you can offset grind a std L series crank 2-3mm undersize, but the pin size starts getting quite small, which in turn can make it hard to find suitable rods & bearing sizes. The beauty of the RB crank is it's a MASSIVE stroke increase with the off-the-shelf con-rod available Quote
CBR Jeff Posted January 25, 2016 Posted January 25, 2016 (edited) What you actually need to take into account with any build is the incidental increase in cost for an item. To say an LCR modified RB crank costs $2700 is correct but the true cost is the biffetence between this price and the other option. In most cases this is reconditioning an old crank. By the time it's crack tested polished balanced checked for alignment etc etc (properly) the price difference to the RB option is probably not as much as it seems. Remembering also that you get a new crank. Another of the advantages of the 89mm option is the availability of very well priced high quality rods that retain a big end journal size that is robust. But each to their own. Edited January 25, 2016 by CBR Jeff Quote
dat2kman Posted January 26, 2016 Posted January 26, 2016 Rod:Stroke ratio? Or dont worry about that,,,, Quote
CBR Jeff Posted January 26, 2016 Posted January 26, 2016 That's why LCR are sorting my build. I would never pretend to understand this but I know Les does. Faz 1 Quote
road rider Posted January 26, 2016 Posted January 26, 2016 What's the weight of the RB crank? I have never seen the RB crank. But if the L series crank is anything to go by.......really heavy Quote
Riceburner Posted January 26, 2016 Posted January 26, 2016 It's probably one for Lurch. Looks as if the counterweights have had a little taken off the ends. gav240z 1 Quote
C.A.R. Posted January 26, 2016 Posted January 26, 2016 I don't actually know. At a guess: 1 - 2kg or so? Quote
Administrators gav240z Posted January 26, 2016 Administrators Posted January 26, 2016 Apparently an LD28 crank is 1 kg heavier than a standard L28 crank.Edit found this post from Nzeder.http://www.viczcar.com/forum/topic/5359-l28-crank-weight/?p=60553 So anything lighter than that has gotta be an improvement. L28 Crank = 20KG LD28 Crank = 22KG Modifed L28 in my old L30 = 19KG Quote
Riceburner Posted January 26, 2016 Posted January 26, 2016 Last two cranks I weighed were virtually the same, both cranks were standard size journals etc. The LD28 crank was 800 grams heavier. LD28=22.8kg's F54 L28=22kgs http://forums.hybridz.org/topic/100131-weight-ld28-crank/ Quote
Riceburner Posted January 26, 2016 Posted January 26, 2016 I don't actually know. At a guess: 1 - 2kg or so? That's pretty good considering the extra stroke! Quote
C.A.R. Posted January 26, 2016 Posted January 26, 2016 That's pretty good considering the extra stroke! Indeed, but the engine acceleration rate these motors have with the bigger stroke makes it inconsequential anyway. Quote
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